Within the field of metal cutting operations, there are known many different ways for minimizing the heat accumulated due to the interaction of a cutting insert with a machined workpiece, in order to prevent the cutting insert from damaging the work-piece and to prevent insert wear, by cooling the operative cutting edge. It is advantageous to deliver a coolant directly to the cutting area, using a cutting tool having a coolant supply, directing a coolant fluid to a cutting edge of the cutting insert.
In addition, it is also necessary to secure the cutting insert to an insert pocket of the cutting tool. U.S. Pat. No. 5,685,672 discloses a cutting tool having a clamp for clamping a cutting insert in an insert pocket. The forward end of the clamp has a first (front) protrusion which engages the wall of a through hole of the insert. The rear end of the clamp has a second (rear) protrusion which engages a sloping surface of the toolholder. A clamp screw extends through the clamp and threadingly engages a bore in the toolholder. When the clamp screw is tightened, the clamp is urged both downwardly and rearwardly and consequently the cutting insert is pushed both downwardly and rearwardly until the cutting insert is firmly secured in the insert pocket. As can be seen in FIG. 2 of U.S. Pat. No. 5,685,672, in a top view of the toolholder, the clamp is not positioned symmetrically with respect to the cutting insert. A line passing through the center of the clamp screw and through the center of the first protrusion, in a top view as seen in FIG. 2 of U.S. Pat. No. 5,685,672, does not pass through the rear corner and operative front corner of the insert. This non-symmetrical positioning stems from the well known three-point support of the cutting insert by the support surfaces (16, 17) of the insert pocket, with one support point on one of the support surfaces (16) and two support points on the other support surface (17). A similar clamping mechanism is disclosed in U.S. Pat. No. 5,100,268 where the non-symmetrical positioning of the clamp relative to the cutting insert can be seen in FIG. 2.
Clamping mechanisms of the type having a front protrusion which engages the wall of a through hole of the insert and a rear protrusion which engages the toolholder are advantageous in that they firmly secure the cutting insert in the insert pocket of the toolholder.
Clamps are ideal for delivering a coolant directly to the cutting area since they are located above the cutting insert close to the cutting area. U.S. Pat. No. 4,848,198 discloses a cutting tool having a bridge-type clamping block which functions both to clamp an insert within a seat and to direct fluid at a produced chip for breaking the chip into segments. The clamping block is not of the type mentioned above. It does not have a front protrusion which engages the wall of a through hole of the insert. Also, the fluid is led through passageways passing through the support bar and requires connecting passageways and a deformable seal to lead the fluid to the discharge orifice.
U.S. Pat. No. 4,621,547 discloses a cutting tool having a clamp which functions both to clamp an insert within a seat and to direct coolant onto the top surface of the insert toward the cutting edge. The clamp has a port which is connected to a coolant delivery line for delivering coolant directly to the clamp. The clamp is not of the type mentioned above. It does not have a front protrusion which engages the wall of a through hole of the insert and it does not have a rear protrusion for engaging the toolholder.